Reductant delivery unit for automotive selective catalytic reduction with gasket anti-deposit shielding structure
a technology of selective catalytic reduction and delivery unit, which is applied in the direction of engines, mechanical equipment, machines/engines, etc., can solve the problems of high nitrogen oxide (nox) emissions of lean-burn engines, difficult to treat ammonia in its pure form in the automotive environment, and the malfunction of the exhaust after-treatment system, so as to prevent urea solution deposit build-up
Active Publication Date: 2015-04-21
VITESCO TECH USA LLC
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Benefits of technology
This patent relates to a method to prevent the buildup of urea solution on a gasket between a reductant delivery unit and an exhaust boss in a vehicle exhaust system. The method involves using a gasket with a hole in it, where the exhaust boss and the reductant delivery unit connect. A shield is placed over the gasket's hole to prevent the urea solution from touching it. This prevents damage to the gasket and ensures the system works properly.
Problems solved by technology
Lean-burn engines exhibit high levels of nitrogen oxide (NOx) emissions that are difficult to treat in oxygen-rich exhaust environments characteristic of lean-burn combustion.
Below a certain threshold temperature, these deposits can build up to the point of obstructing the injected urea solution spray, resulting in a malfunction of the exhaust after-treatment system.
In some cases, these deposit growths may progress to obstruct the through-hole entirely.
Method used
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Embodiment Construction
[0014]With reference to FIG. 1, an RDU is shown, generally indicated at 10, in accordance with an embodiment of the invention. The RDU 10 can be employed in a diesel dosing system of the type disclosed in U.S. Pat. No. 7,721,533, the contents of which is hereby incorporated by reference into this specification.
[0015]The RDU 10 includes a solenoid fluid injector 12 that provides a metering function of fluid and provides the spray preparation of the fluid into the exhaust path of a vehicle in a dosing application. Thus, the fluid injector 12 is constructed and arranged to be associated with an exhaust gas flow path upstream of a SCR catalytic converter. The fluid injector 12 is preferably a gasoline, electrically operated, solenoid fuel injector such as the type disclosed in U.S. Pat. No. 6,685,112, the content of which is hereby incorporated by reference into this specification.
[0016]The fluid injector 12 is welded to an interior carrier 14. An inlet cup structure 16 is fixed to a sh...
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A reductant delivery unit (10) includes a fluid injector (12) and a flange (20) coupled with the fluid injector. An exhaust boss (28) has a surface (39) defining a through-hole (40) that communicates with a vehicle's exhaust flow path. The flange is coupled to a mounting surface such that the outlet of the fluid injector communicates with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. A gasket (32) is sandwiched between the flange and the mounting surface. The gasket has a surface (37) defining a through-hole (38) therein that communicates with the through-hole in the exhaust boss to permit the urea solution to pass from the fluid outlet to the exhaust flow path. Gasket shielding structure (44) covers the surface defining the through-hole in the gasket to prevent the urea solution from contacting the gasket.
Description
FIELD OF THE INVENTION[0001]The invention relates to a reductant delivery unit (RDU) that supplies reductant to an engine exhaust system and, more particularly, to a shield associated with a gasket, between an RDU and an exhaust boss, to minimize insoluble urea solution deposits on the gasket.BACKGROUND OF THE INVENTION[0002]The advent of a new round of stringent emissions legislation in Europe and North America is driving the implementation of new exhaust after-treatment systems, particularly for lean-burn technologies such as compression-ignition (diesel) engines, and stratified-charge spark-ignited engines (usually with direct injection) that are operating under lean and ultra-lean conditions. Lean-burn engines exhibit high levels of nitrogen oxide (NOx) emissions that are difficult to treat in oxygen-rich exhaust environments characteristic of lean-burn combustion. Exhaust after-treatment technologies are currently being developed that will treat NOx under these conditions. One ...
Claims
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IPC IPC(8): F01N3/00F01N3/20F01N13/18
CPCF01N3/2066F01N13/1827F01N2610/02F01N2610/1453Y02T10/24Y02A50/20Y02T10/12
Inventor BUGOS, STEPHEN C.HORNBY, MICHAEL J.
Owner VITESCO TECH USA LLC